The number and types of electronic devices available to consumers has increased tremendously the past few years, and that rate of increase shows no signs of abating any time soon. These electronic devices include portable devices, such as laptop, netbook, or tablet computers, cell, media, or smart phones, global positioning devices, media players, and other such devices.
These portable devices need to be supplied power during operation, and this power may come from external sources or internal sources, such as batteries. These batteries typically need to be charged using an external source, such as a power adapter. These power adapters may receive AC power from a wall outlet, car charger, or other source, and provide DC power that may be used to charge batteries.
But some devices, such as laptop computers, are very computationally powerful, and therefore require a fair amount of power. Complicating this further is the fact that users of these laptops want to be able to run their laptops for extended periods of time without having to recharge the batteries. Moreover, when a user does connect to a power source to charge the batteries, it is likely the user wants to have the batteries charge very quickly so that the user is free to disconnect from the power source.
For these reasons, many newer electronic devices have relatively large batteries. Accordingly, it has become desirable to be able to provide large amounts of charging power very quickly.
But this quick charging is not without its drawbacks. For example, this quick charging may cause high temperatures in a power adapter. To cool the power adapter, the power adapter may need to be made fairly large, such that heat may be dissipated. To avoid this, it may be desirable for an electronic device to control or adjust the power adapter in order to maintain the temperature of the power adapter.
Thus, what is needed are circuits, methods, and apparatus that allow an electronic device to control a power adapter.